/*
**
** Copyright 2007, The Android Open Source Project
**
** Licensed under the Apache License, Version 2.0 (the "License");
** you may not use this file except in compliance with the License.
** You may obtain a copy of the License at
**
**     http://www.apache.org/licenses/LICENSE-2.0
**
** Unless required by applicable law or agreed to in writing, software
** distributed under the License is distributed on an "AS IS" BASIS,
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
** See the License for the specific language governing permissions and
** limitations under the License.
*/
package com.android.packageinstaller.television;

import android.app.Activity;
import android.app.admin.IDevicePolicyManager;
import android.content.Context;
import android.content.Intent;
import android.content.pm.ApplicationInfo;
import android.content.pm.IPackageDeleteObserver;
import android.content.pm.IPackageDeleteObserver2;
import android.content.pm.IPackageManager;
import android.content.pm.PackageInstaller;
import android.content.pm.PackageManager;
import android.content.pm.UserInfo;
import android.graphics.Color;
import android.graphics.drawable.ColorDrawable;
import android.os.Bundle;
import android.os.Handler;
import android.os.IBinder;
import android.os.Message;
import android.os.RemoteException;
import android.os.ServiceManager;
import android.os.UserHandle;
import android.os.UserManager;
import android.util.Log;
import android.util.TypedValue;
import android.view.KeyEvent;
import android.widget.Toast;

import com.android.packageinstaller.PackageUtil;
import com.android.packageinstaller.R;

import java.lang.ref.WeakReference;
import java.util.List;

/**
 * This activity corresponds to a download progress screen that is displayed
 * when an application is uninstalled. The result of the application uninstall
 * is indicated in the result code that gets set to 0 or 1. The application gets launched
 * by an intent with the intent's class name explicitly set to UninstallAppProgress and expects
 * the application object of the application to uninstall.
 */
public class UninstallAppProgress extends Activity {
    private static final String TAG = "UninstallAppProgress";

    private static final String FRAGMENT_TAG = "progress_fragment";

    private ApplicationInfo mAppInfo;
    private boolean mAllUsers;
    private IBinder mCallback;

    private volatile int mResultCode = -1;

    /**
     * If initView was called. We delay this call to not have to call it at all if the uninstall is
     * quick
     */
    private boolean mIsViewInitialized;

    /** Amount of time to wait until we show the UI */
    private static final int QUICK_INSTALL_DELAY_MILLIS = 500;

    private static final int UNINSTALL_COMPLETE = 1;
    private static final int UNINSTALL_IS_SLOW = 2;

    private Handler mHandler = new MessageHandler(this);

    private static class MessageHandler extends Handler {
        private final WeakReference<UninstallAppProgress> mActivity;

        public MessageHandler(UninstallAppProgress activity) {
            mActivity = new WeakReference<>(activity);
        }

        @Override
        public void handleMessage(Message msg) {
            UninstallAppProgress activity = mActivity.get();
            if (activity != null) {
                activity.handleMessage(msg);
            }
        }
    }

    private void handleMessage(Message msg) {
        if (isFinishing() || isDestroyed()) {
            return;
        }

        switch (msg.what) {
            case UNINSTALL_IS_SLOW:
                initView();
                break;
            case UNINSTALL_COMPLETE:
                mHandler.removeMessages(UNINSTALL_IS_SLOW);

                if (msg.arg1 != PackageManager.DELETE_SUCCEEDED) {
                    initView();
                }

                mResultCode = msg.arg1;
                final String packageName = (String) msg.obj;

                if (mCallback != null) {
                    final IPackageDeleteObserver2 observer = IPackageDeleteObserver2.Stub
                            .asInterface(mCallback);
                    try {
                        observer.onPackageDeleted(mAppInfo.packageName, mResultCode,
                                packageName);
                    } catch (RemoteException ignored) {
                    }
                    finish();
                    return;
                }

                if (getIntent().getBooleanExtra(Intent.EXTRA_RETURN_RESULT, false)) {
                    Intent result = new Intent();
                    result.putExtra(Intent.EXTRA_INSTALL_RESULT, mResultCode);
                    setResult(mResultCode == PackageManager.DELETE_SUCCEEDED
                            ? Activity.RESULT_OK : Activity.RESULT_FIRST_USER,
                            result);
                    finish();
                    return;
                }

                // Update the status text
                final String statusText;
                switch (msg.arg1) {
                    case PackageManager.DELETE_SUCCEEDED:
                        statusText = getString(R.string.uninstall_done);
                        // Show a Toast and finish the activity
                        Context ctx = getBaseContext();
                        Toast.makeText(ctx, statusText, Toast.LENGTH_LONG).show();
                        setResultAndFinish();
                        return;
                    case PackageManager.DELETE_FAILED_DEVICE_POLICY_MANAGER: {
                        UserManager userManager =
                                (UserManager) getSystemService(Context.USER_SERVICE);
                        IDevicePolicyManager dpm = IDevicePolicyManager.Stub.asInterface(
                                ServiceManager.getService(Context.DEVICE_POLICY_SERVICE));
                        // Find out if the package is an active admin for some non-current user.
                        int myUserId = UserHandle.myUserId();
                        UserInfo otherBlockingUser = null;
                        for (UserInfo user : userManager.getUsers()) {
                            // We only catch the case when the user in question is neither the
                            // current user nor its profile.
                            if (isProfileOfOrSame(userManager, myUserId, user.id)) continue;

                            try {
                                if (dpm.packageHasActiveAdmins(packageName, user.id)) {
                                    otherBlockingUser = user;
                                    break;
                                }
                            } catch (RemoteException e) {
                                Log.e(TAG, "Failed to talk to package manager", e);
                            }
                        }
                        if (otherBlockingUser == null) {
                            Log.d(TAG, "Uninstall failed because " + packageName
                                    + " is a device admin");
                            getProgressFragment().setDeviceManagerButtonVisible(true);
                            statusText = getString(
                                    R.string.uninstall_failed_device_policy_manager);
                        } else {
                            Log.d(TAG, "Uninstall failed because " + packageName
                                    + " is a device admin of user " + otherBlockingUser);
                            getProgressFragment().setDeviceManagerButtonVisible(false);
                            statusText = String.format(
                                    getString(R.string.uninstall_failed_device_policy_manager_of_user),
                                    otherBlockingUser.name);
                        }
                        break;
                    }
                    case PackageManager.DELETE_FAILED_OWNER_BLOCKED: {
                        UserManager userManager =
                                (UserManager) getSystemService(Context.USER_SERVICE);
                        IPackageManager packageManager = IPackageManager.Stub.asInterface(
                                ServiceManager.getService("package"));
                        List<UserInfo> users = userManager.getUsers();
                        int blockingUserId = UserHandle.USER_NULL;
                        for (int i = 0; i < users.size(); ++i) {
                            final UserInfo user = users.get(i);
                            try {
                                if (packageManager.getBlockUninstallForUser(packageName,
                                        user.id)) {
                                    blockingUserId = user.id;
                                    break;
                                }
                            } catch (RemoteException e) {
                                // Shouldn't happen.
                                Log.e(TAG, "Failed to talk to package manager", e);
                            }
                        }
                        int myUserId = UserHandle.myUserId();
                        if (isProfileOfOrSame(userManager, myUserId, blockingUserId)) {
                            getProgressFragment().setDeviceManagerButtonVisible(true);
                        } else {
                            getProgressFragment().setDeviceManagerButtonVisible(false);
                            getProgressFragment().setUsersButtonVisible(true);
                        }
                        // TODO: b/25442806
                        if (blockingUserId == UserHandle.USER_SYSTEM) {
                            statusText = getString(R.string.uninstall_blocked_device_owner);
                        } else if (blockingUserId == UserHandle.USER_NULL) {
                            Log.d(TAG, "Uninstall failed for " + packageName + " with code "
                                    + msg.arg1 + " no blocking user");
                            statusText = getString(R.string.uninstall_failed);
                        } else {
                            statusText = mAllUsers
                                    ? getString(R.string.uninstall_all_blocked_profile_owner) :
                                    getString(R.string.uninstall_blocked_profile_owner);
                        }
                        break;
                    }
                    default:
                        Log.d(TAG, "Uninstall failed for " + packageName + " with code "
                                + msg.arg1);
                        statusText = getString(R.string.uninstall_failed);
                        break;
                }
                getProgressFragment().showCompletion(statusText);
                break;
            default:
                break;
        }
    }

    private boolean isProfileOfOrSame(UserManager userManager, int userId, int profileId) {
        if (userId == profileId) {
            return true;
        }
        UserInfo parentUser = userManager.getProfileParent(profileId);
        return parentUser != null && parentUser.id == userId;
    }

    @Override
    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);

        Intent intent = getIntent();
        mAppInfo = intent.getParcelableExtra(PackageUtil.INTENT_ATTR_APPLICATION_INFO);
        mCallback = intent.getIBinderExtra(PackageInstaller.EXTRA_CALLBACK);

        // This currently does not support going through a onDestroy->onCreate cycle. Hence if that
        // happened, just fail the operation for mysterious reasons.
        if (icicle != null) {
            mResultCode = PackageManager.DELETE_FAILED_INTERNAL_ERROR;

            if (mCallback != null) {
                final IPackageDeleteObserver2 observer = IPackageDeleteObserver2.Stub
                        .asInterface(mCallback);
                try {
                    observer.onPackageDeleted(mAppInfo.packageName, mResultCode, null);
                } catch (RemoteException ignored) {
                }
                finish();
            } else {
                setResultAndFinish();
            }

            return;
        }

        mAllUsers = intent.getBooleanExtra(Intent.EXTRA_UNINSTALL_ALL_USERS, false);
        UserHandle user = intent.getParcelableExtra(Intent.EXTRA_USER);
        if (user == null) {
            user = android.os.Process.myUserHandle();
        }

        PackageDeleteObserver observer = new PackageDeleteObserver();

        // Make window transparent until initView is called. In many cases we can avoid showing the
        // UI at all as the app is uninstalled very quickly. If we show the UI and instantly remove
        // it, it just looks like a flicker.
        getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
        getWindow().setStatusBarColor(Color.TRANSPARENT);
        getWindow().setNavigationBarColor(Color.TRANSPARENT);

        try {
            getPackageManager().deletePackageAsUser(mAppInfo.packageName, observer,
                    mAllUsers ? PackageManager.DELETE_ALL_USERS : 0, user.getIdentifier());
        } catch (IllegalArgumentException e) {
            // Couldn't find the package, no need to call uninstall.
            Log.w(TAG, "Could not find package, not deleting " + mAppInfo.packageName, e);
        }

        mHandler.sendMessageDelayed(mHandler.obtainMessage(UNINSTALL_IS_SLOW),
                QUICK_INSTALL_DELAY_MILLIS);
    }

    public ApplicationInfo getAppInfo() {
        return mAppInfo;
    }

    private class PackageDeleteObserver extends IPackageDeleteObserver.Stub {
        public void packageDeleted(String packageName, int returnCode) {
            Message msg = mHandler.obtainMessage(UNINSTALL_COMPLETE);
            msg.arg1 = returnCode;
            msg.obj = packageName;
            mHandler.sendMessage(msg);
        }
    }

    public void setResultAndFinish() {
        setResult(mResultCode);
        finish();
    }

    private void initView() {
        if (mIsViewInitialized) {
            return;
        }
        mIsViewInitialized = true;

        // We set the window background to translucent in constructor, revert this
        TypedValue attribute = new TypedValue();
        getTheme().resolveAttribute(android.R.attr.windowBackground, attribute, true);
        if (attribute.type >= TypedValue.TYPE_FIRST_COLOR_INT &&
                attribute.type <= TypedValue.TYPE_LAST_COLOR_INT) {
            getWindow().setBackgroundDrawable(new ColorDrawable(attribute.data));
        } else {
            getWindow().setBackgroundDrawable(getResources().getDrawable(attribute.resourceId,
                    getTheme()));
        }

        getTheme().resolveAttribute(android.R.attr.navigationBarColor, attribute, true);
        getWindow().setNavigationBarColor(attribute.data);

        getTheme().resolveAttribute(android.R.attr.statusBarColor, attribute, true);
        getWindow().setStatusBarColor(attribute.data);

        boolean isUpdate = ((mAppInfo.flags & ApplicationInfo.FLAG_UPDATED_SYSTEM_APP) != 0);
        setTitle(isUpdate ? R.string.uninstall_update_title : R.string.uninstall_application_title);

        getFragmentManager().beginTransaction()
                .add(android.R.id.content, new UninstallAppProgressFragment(), FRAGMENT_TAG)
                .commitNowAllowingStateLoss();
    }

    @Override
    public boolean dispatchKeyEvent(KeyEvent ev) {
        if (ev.getKeyCode() == KeyEvent.KEYCODE_BACK) {
            if (mResultCode == -1) {
                // Ignore back key when installation is in progress
                return true;
            } else {
                // If installation is done, just set the result code
                setResult(mResultCode);
            }
        }
        return super.dispatchKeyEvent(ev);
    }

    private ProgressFragment getProgressFragment() {
        return (ProgressFragment) getFragmentManager().findFragmentByTag(FRAGMENT_TAG);
    }

    public interface ProgressFragment {
        void setUsersButtonVisible(boolean visible);
        void setDeviceManagerButtonVisible(boolean visible);
        void showCompletion(CharSequence statusText);
    }
}